Divers are leaving Bluff in about an hour to plug air vents in the fuel tanks of the fishing vessel Torea, which remains semi-submerged close to the shore of Ruapuke Island in Foveaux Strait.

An assessment at first light this morning shows a small slick of diesel from the Torea, Environment Southland Regional On-Scene Commander Dallas Bradley said. It seems that the diesel is continuing to come from the fuel tank "breathers" rather than from any rupture in the tank itself, but that will be confirmed once divers have inspected the hull. The 20-knot northerly winds are blowing the diesel offshore, where it will disperse naturally. In the current conditions there is no concern that the small amount of diesel in the water would harm the environment or wildlife.

Mr Bradley said discussions with the vessel's owner, Campbelltown Seafood, and its insurer had resulted in an agreement that plugging the fuel tank breathers would be a priority once divers reached the Torea. this morning. "Our priority is still to prevent any spillage of diesel from the Torea," he said.

Mr Bradley said that he had talked to the boat's skipper, Peter Leask, and established that there was less diesel than the 3000 litres originally thought to be on board the Torea . The amount is now estimated to be closer to 2500 litres. Also, there was a total of 23 people on the vessel when it struck a rock yesterday - 20 passengers and three crew.

Mr Bradley said interim plans to salvage the vessel were being made overnight and he expected to know more once the divers had assessed the hull today.

The vessel appears to be in the same position on the seabed, partly submerged and listing to port but stable.